The objectives of the proposed studies are to gain insight into the mechanisms involved in the control and integration of the primate hypothalamic-pituitary target tissue axes during intrauterine life and infancy. For studies in utero, the chronically catheterized fetal monkey will be employed. Endocrine regulation of the pituitary-adrenal and pituitary-gonadal systems will be studied, and the possible role of the pituitary-adrenal system in primate fetal lung maturation and initiation of labor investigated. Studies also will be performed concerning maturation and changing sensitivity of the pituitary-adrenal and pituitary-gonadal system in the fetal and infant monkey, and the factors modulating these changes.